Posted on Dec 30, 2019 in Cosmos, Science
Is the universe destined to collapse, ending in a big crunch or to expand indefinitely until it homogenizes in a heat death? Sir Roger Penrose, Emeritus Professor at the Mathematical Institute of the University of Oxford explains a third alternative, the cosmological conformal cyclic cosmology (CCC) – where the universe evolves through eons, each ending in the decay of mass and beginning again in a new Big Bang.
Penrose has made profound contributions across a broad range of scientific disciplines, encompassing geometry, black hole singularities, the unification of quantum mechanics and gravity, the structure of space-time and the origin of our universe.
The equations governing the crossover from each aeon to the next demand the creation of a dominant new scalar material, postulated to be dark matter. In order that this material does not build up from aeon to aeon, it is taken to decay away completely over the history of each aeon.
The dark matter particles, dubbed erebons by Penrose, may be expected to behave almost as classical particles, though with bosonic properties; they would probably be of about a Planck mass and interacting only gravitationally. Their decay would produce gravitational signals and be responsible for the approximately scale invariant temperature fluctuations in the CMB of the succeeding aeon.
This past January, The Daily Galaxy posted Dark Matter –Emerged From an Eon Before the Big Bang, describing Penrose’s Erebon field theory, a novel explanation of dark matter. Despite a decade of searches, no signs of a dark matter particle have turned up.
Dark Matter –“Emerged From an Eon Before the Big Bang”
In our own eon, erebon decay might show up in signals discernable by gravitational wave detectors, such as LIGO and VIRGO.
The Greek god of darkness was Erebus, one of the primordial deities in Greek mythology, born out of Chaos, the primeval void, foreshadowing the contemporary, emerging reality of the dark side of our universe. Penrose believes we will be able to find some dark force, a portal into the dark world. Such a “dark photon” would be dark matter’s equivalent of a photon, the way that dark matter particles interact with one another.
“Dark photon searches are simultaneously straightforward and challenging, straightforward because the concept is general and simple enough that designing experimental searches is pretty easy, but challenging because we really have no clue where in the parameter space the dark photon could live,” says CERN Physicist James Beacham.
Penrose, reported Physics World, proposes a solution that points to the existence of an aeon before the Big Bang. Correlated noise in the two LIGO gravitational-wave detectors may provide evidence that the universe is governed by conformal cyclic cosmology (CCC) which assumes that the universe consists of a succession of aeons, “the boundaries of infinity,” speculates Penrose. “The Big Bang was not the origin of our universe,” he observed.
The apparent noise is actually a real signal of gravitational waves generated by the decay of hypothetical dark-matter particles predicted by CCC from a previous eon that can be seen in the cosmic microwave background –electromagnetic radiation left over from an early stage of the universe in Big Bang cosmology.
Penose argues that a significant amount of this noise could be a signal of astrophysical or cosmological origin – and specifically CCC.
Physicists at the Niels Bohr Institute, writes Hamish Johnston, editor of physicsworld.com, pointed out that some of the noise in the two LIGO detectors appears to be correlated – with a delay that corresponds to the time it takes for a gravitational wave to travel the more than 3000 kilometers between the instruments.
First proposed over a decade ago by Penrose, CCC assumes that each aeon begins with a big bang and proceeds into an unending future in which the universe expands at an accelerating rate. As this expansion becomes infinitely large, Penrose argues that it can be transformed back into the next big bang.
Penrose, Johnston writes, says that a “reasonably robust implication of CCC” is that dark matter consists of particles called erebons. As dark matter goes, erebons are extremely heavy and have masses of about 10–5 g. This is roughly the Planck mass and on a par with a grain of sand and about 22 orders of magnitude heavier than a proton.
When an erebon decays, Penrose states, it deposits all its energy into a gravitational wave frequencies well above the detection capabilities of LIGO, and would be detected and recorded as near-instantaneous impulses that could be mistaken for noise rather than a signal from the birth of the cosmos.
The Daily Galaxy, Sam Cabot, via NASA, Physics World, Arxiv.org(PenrosePDF) and Physics Forums